Facsimile apparatus



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OHARLSJ al R065 OLDE/V United States PatentA Oce 2,693,992 Patented Nov.9, 1954 i FACSIMILE ABPARATUS Charles J. Young andRogenG..Oldeu1rinceton, N. J.,

assignors to, Radio Corporation-,d A-merica, a corporationof Delaware4iflpplieation July 7,'"1948," Serial No. 37,3.84 9 ClaimS.- (Cl.346-10.1.)

simultaneously to produce marks. ona recordingl medium contacted by theelectrodesof the couple.y The invention is also concerned withandrelates to novel forms of electrode mountings.

in thedisclosed forms, the inventionk isparticularly adapted to thatform of facsimile recording,apparatus wherein the reproduced messageisbuilt up in a point by point manner on arecording paper or strip byreason of current flowing through the strip or paper upon which themessage is to be produced. Such forms of systems are usually those wherethe recording on ther-record strip takes place by reasonof a currentflowing directly through the medium upon which the record is to beproduced, and, accordingly, such systems are generally known irl-the artas recorders of the so-called electrolytic type,,although it is to beunderstood that in some instances the recordings may develop as a resultofV heat. or'the like produced by current flowingbetween two suitable`electrodes with the recording material interposed therebetween.l

ln apparatus of this general type, it has been customary, as known inthe art, to provide a record drum -uponwhich is suitably arranged ahelical stripvwhich lextendsusually fromone end of the drum tothe otherand covers substantially 360 of the drum.

The drum may have several helices whichcooperate with an electrodelknown variously as :a printer bar or apresser bar. The helix and theprinterbar ,together provide what may be regarded as Va recording orprinting couple. lf a plurality of helices are used; orV ifthc printervbar cooperatesvwith a single helixvatmorexthan one point, it willthenibe- .obvious :thatla plurality of printing couples are present. ingrecordingsby the methods discussedr above, a certain amount of pressureis applied to squeezetherecording medium,A such as paper, between the`printen bar Vand helix, or helices, so thatthe electrical resistancethrough the paper from one to the other shall.be relatively low.

This pressure, if it is too high, will shear or damage `the sheet. Ifboth the printer bar and the helix yare rigidly mounted, itisimpractical to maintain theirarrangement with such precisionthatthepaper squeeze is constant. Also, there is a tendency to tear thepaper at the side where the advancing helix pushes. under the end of theprinter bar. Heretoforc, in-theI prior art; it has been customary tomake the printer bar in the form of'a -strip mounted in a plane throughthe axisiofthey helix, and to support itin a hinged frame, or in a slot,Vand then ,to apply adequate pressure by springs. At modernhighrecording speeds in the vicinity of 1200 R. P. M. to 2000 R. P. M. forthe helix drum, the printer bar is easily shocked into oscillation; andbecause of its considerable mass, it can only be restrainedfrom-oscillation byincreasing the spring pressure to a .point where vthepaper may be damaged.

Thev diiculty .of maintainingv a uniform. and. nonoscillating contactpressure in the recording c ouple has been heretofore one ofthe majorlimitations in building electrolytic facsimileY recorders for-very highspeed 0peration.

In accordance with the invention, therefore, a printer bar of novelconstructionis lprovided/which is ilexible radially of the helix butwhichz'is. stiff laterally of the printer bar structure andtangentially, of the helix.Vv In For thel purposefofr obtainnormal useof the recording or printing couple comprisinga printer bar and helix,the recording medium is-in general tangential to the helix, orfollows-the surface of the helix. Moreover, the printer bar of thisinvention has the further advantages of being easily adjustable,self-insulating, and relatively quiet in operation in a high-speedrecorder. In accordance with the invention, the total mass of thevprinter bar is much less and its vertical stiffness is lgreatly reducedwithout sacrificing the lateral rigidity which insures a straightrecorded line across the sheet. Consequently, the effective massreacting against the helix at any point is only a fraction of the totalfor the bar. Added to this is the damping effect of f the novel mountingarrangement disclosed herein. As a result, ktherevis practically notendency for the printer bar of this invention to vibrate even at highdrum speeds, and a uniform contact pressure can be maintained along itslength. Uniform contact pressure along the length ofthe yprinter bar,when the bar serves to provide one element of one or more recordingcouples traversing the bar simultaneously and at a very high speedlinearly of the bar, is maintained with a bar constructed in accordancewith this invention. It will be understood that while a helix or helicesare described herein by way of example, the cooperating electrode orelectrodes may have another form and provide a moving point or points ofcontact with the bar of suitable elemental image areas.

Inits application to the so-called electrolytic type of recording, as isillustrated in one form, for instance, by Young Patent No. 2,215,806, arecording sheet or strip is arranged to be impregnated with a chemicalsolution which issuitably changed when picture modulated signal currentows through it in the reproduction of the picture image, so thatmarkingeffects are obtained upon the material.. of the. recording sheet. Theimpregnated paper issuitably advanced relative to the recording drum andthe printer bar so as to bring new'sections of the re cording strip.continuously beneath the printer bar. Sig nal energy, as it is receivedfrom the communication channel after being suitably amplified, is causedto initiate the ilowcf current between the printer baron the one hand,serving as one, electrode of the system, and the recording helix on thehelix drum, serving as the other electrode, on the other hand. Thedensity of the marking in the recordingy strip is, generally speaking,proportional tothe intensity of the current owing.

The principalobject of the present invention, therefore, is to provide aprinter bar of novel 'construction which is flexible in a plane normalto the surface of the recording medium upon which the bar rests but isrela tively rigid in Va plane parallel to the recording surface of therecording medium.

A further object of the invention is to provide a novel printer barwhich is generally T-shaped in cross-section.

A still further object of the invention is to provide a novel printerbar mounting which permits full advantage tol be taken of theflexibility characteristics of the bar of thepresent invention.

Still another object of the invention is to provide a novel adjustablemounting for the printer bar.

Other objects and advantages of the present invention will,--of course,become apparent and immediately suggest themselves to those skilled inthe art to which the in lentionis directed from a reading of thefollowing specicationin connection with the accompanying draw ingin-which:

Fig.` l isa view in` frontelevation of the printer bar and printer barmounting of this invention in conjunction with a recordingl or helixcarrying drum;

Fig-2 is a bottom plan View of` the printer barand printer bar mountingof Fig. l with the drum omitted for thesake of convenience ofillustration;

Fig. 3 is a View in cross-section on line 3 3 of Fig. l;

Fig,f,4 is a view of front elevation of another embodiment of theprinter bar mounting of this-invention;

Fig. 5 is a View in cross-section on line 5-5 of Fig. 4;

Fig. 6 is a View in front elevation of a further embodiment of theprinter bar mounting of the invention; and

Fig. 7 is a view in cross-section taken on line 7 3/ of Fig. .6;

Referring` forthe present to Fig. l of the drawing,

there is shown fragmentarily, and by way of example, a recorder which issuitable for producing marks in accordance with facsimile signals. Thisrecorder may be, generally of the character described in U. S. PatentNo. 2,215,806 granted to Charles I. Young on September 24, 1940. Byreason of the invention disclosed herein, a considerable improvement inthe method of obtaining the nal record and in the` apparatus whichembodies features for carrying out the improved method is presented overthe general disclosure of the above noted Patent No. 2,215,806 and otherpatents showing prior art electrical recording arrangements.

In the form shown, the recorder comprises a recording drum 12, providedwith a radially projecting helical electrode 14 mounted on its peripherywhich cooperates with a second electrode in the form of a printer bar16. The drum 12 may have additional helices thereon, for example,another helix 17. This printer bar member is carried by novel means ofthe present invention indicated generally by the reference character 18.The means 18 are secured on any convenient stationary portions 19 and 20of the apparatus in a manner to be described.

Reference character 23 designates a signal or facsimile receiver of anyknown type, radio or wire line, which is in communication with a signalinput source 24.

The incoming signal may be composed of a number of carriers, two forexample, each having image or other intelligence modulated thereon forrecording. The nature of this intelligence is not of importance inconnection with the description of the present invention. Each carriermay, for example, be modulated with signals derived as a result ofscanning subject copy by a color separation method. Several of thesemethods are known to the prior art. The carriers are separated in achannel separator 26 and demodulators 27 and 28 derive signals suitablefor recording. These latter signals are applied to the helices 14 and 17over conductors 31 and 32 which are connected to brushes 34 and 36. Thehelices 14 and 17 are connected to slip rings 38 and 39 upon which thebrushes 34 and 36 bear. It will be understood that the helices will beinsulated from the drum 12, or the latter may be made of insulatingmaterial. In the illustrative arrangement, the printer bar 16 isconnected to a common circuit point, such as ground, for example.However, for a single helix, one of the connections 41 from the receiver23 which may then incorporate a suitabledemodulator, may be incommunication with a brush which bears on the drum shaft 43, or theframe of the apparatus (not shown) and the other terminal or connection41 from the receiver 23 may be connected to the printer bar 1.

16 to complete the connection to the recording electrodes. 1t will beunderstood that the single helix will then be conductively connected tothe drum shaft and the printer bar 16 will be insulated.

The record sheet or paper web 46 which is threaded between the printerbar 16 and the helical electrode or electrodes is drawn through therecording zone by suitable means (not shown). The drum and paper feedmeans may be driven in a coordinated manner by suitable means (notshown). Patent Number 2,215,806 referred to above shows such means aswell as paper drive means. synchronizing and phasing signals may begenerated and transmitted as described in U. S. Patent 2,326,740 grantedto Maurice Artzt on August 17, 1943, when desirable or necessary.

Since the elements so far described are well known, per se, andgenerally of themselves do not form the particular basis of thisinvention, they are illustrated herein more or less diagramically.Further details of the helical recorder with respect to the paperfeeding means and other conventional features are to be found in U. S.Patent Re. 20,152 granted to the present inventor on October 27, 1936.TheA recorder in this last named patent, however, relies on a transferof marking material to produce markings by Vibrating the printer barrather than on electrical or other processes which depend upon a directapplication of electrical effects to the record sheet. Other details ofa facsimile recorder employing an electrolytic process for producingmarks are shown in U. S. Patent 2,391,765 granted to Maurice Artzt onDecember 26, 1945. A suitable recording solution is disclosed andclaimed in the copending application of Myer Solomon, Serial No.469,960, led December 23, 1942. This Solomon application is a divisionof the application now Patent No. 2,306,471 granted December 29, 1942.

The printer bar 16 together with the printer bar carrier means 18, bothof this invention, will be now described in detail. The printer bar 16of the invention is or may be in effect a composite structure comprisinga resilient strip 52 to which is secured metallic strip 53. The strip 53may be formed by flattening a wire. The strip 52 is preferably of metal.The ilattened wire is or may be joined to the strip by a series ofspaced spot welds, or the T-shaped section may be formed from one piece.It will be noted that the entire electrode 16 is resilient in adirection normal to the plane of the strip 52 but by reason of itsstructure it is relatively rigid in a direction parallel to the strip52. These are desirable characteristics for a recording electrode. Thematerial of both the strip 52 and the flattened wire 53 is preferablyselected with regard to physical properties such as resilience, and,with respect to the flattened wire, it must resist local heating andcorrosion at the recording points. Suggested material for this purposeis a nickel-chromium alloy. Other embodiments of the invention to bediscussed hereinafter include showings of a unitary or integral printerbar 16 having the genral physical shape of the printer bar of Fig. l.

The support for the printer bar 16 is, in accordance with the invention,a yielding membrane 56 upon which the strip 52 is cemented or otherwisesecured in intimate contact therewith. This membrane is preferably freeand unsupported over a portion of its area on its side opposite from theelectrode. One way of achieving this result is indicated in Fig. 1 ofthe drawings wherein the membrane 56 is cemented or otherwise secured tothe face of a supporting member 58 which is slotted as indicated byreference character 59, this slot being centered with respect to theflattened wire 53. While a slot 59 has been shown, it will be understoodthat the member 5S may merely be grooved or otherwise formed to providerelief in the supporting surface opposite to the printer bar 16.

In View of the resilient nature of the electrode 16 and the dampingelect of the membrane 56 it is unnecessary, with the printer bar of thisinvention, as has been pointed out above, to mount the bar in any sortof hinged or springy mounting. In fact, such a mounting is not onlyunnecessary but is undesirable inasmuch as it may be set into vibrationif the drum 12 operates at modern high recording speeds in theneighborhood of 1600 to 2000 R. P. M. In the illustrative example themember 58 is more or less rigidly secured to the previously mentionedmachine parts 19 and 20 by suitable fastening means such as screws 61.Adjustment of the position of the electrode 16 with respect to the helixor helices and with respect to the drum 12 is provided by adjustingscrews 62 the latter being engaged in tapped holes in the member 58.

The printer bar 16 is insulated from the supporting member 58 where themembrane 56 is formed of natural rubber or a synthetic product such asneoprene. An insulated terminal connection for the bar 16 isconveniently provided by a post 64 which is mounted within a bushing orcollar 66 of insulating material. One end of the electrode 16 or aseparate metallic piece 67 connected to it is fastened by suitable meanssuch as a screw 68 to the post 64. Where the printer bar may be groundedin operation, an additional metallic piece 71 is secured as by a screw72 to the'supporting member 58 and is in contact with the end of theelectrode 16. In this latter case, the terminal post is not needed.

Fig. 3 of the drawings, which shows the electrode 16 and the membrane 56in cross-section, indicates the space between the edge of the slot 59and the strip 52 and in this region the membrane is in shear. Thisconstruction takes full advantage of the damping character of themembrane in shear. For example, the membrane may be selected so that areading of to 60 is obtained on a Shore durometer when the material istested.

Stated in other words, the relation of the width of the relief groove tothe width of the strip 52 is important. The membrane 56 of rubber hasits best damping effect in shearand this occurs between the edge of 52and the edge of the groove. At present we use for 52 1A" and for thegroove 3%". The ratio groove width 52 Width 1 and 2 ment of theinvention in which the tension of the membrane in a direction parallelto the plane of the part of the printer bar corresponding to the strip`52 is adjustable. The printer bar 76 corresponds in physicalcharacteristics to tlie printer bar 16 of Fig. 1, but is of unitary orintegral construction comprising a flat portion 78 and a ridge 79 whichserves to Contact the recording medium or paper 46. This printer bar 76is cemented or otherwise intimately secured to a membrane 81 of naturalrubber, neoprene or the like. This membrane is drawn around a supportingchannel 82 and its ends are clamped in position against the top of thechannel by a rigid strip 84 held in place by suitable fastening meanssuch as screws 86. The channel 82 slidably receives a stretching member88 within its groove, the position of the stretching member being madeadjustable by suitable means such as adjusting screws 91.

The stretching member 88 is grooved as indicated at 93, this groovecorresponding in function to the slot 59 shown in Fig. 1 of thedrawings. As the screws 91 are turned down, the membrane 81 may beplaced under increasing tension. With the arrangement of Fig. 4 thetension in the membrane may be increased by turning the adjusting screws91. This latter eifect increases the effective stiness of the resilientsupport for the printer bar which is provided by the material in shearbetween the edgs of the flat portion 78 and the boundary of the groove93.

The channel 82 may be supported as shown by Fig. 1 of the drawings inwhich case the pressure of the printer bar on the paper can beindependent of the setting of the membrane tension adjusting screws 91.The bar 76 and channel 82 may be moved bodily with respect to the drumand the helix or helices thereon.

Figs. 6 and 7 of the drawings show a further embodiment of the inventioninvolving another arrangement for adjusting the tension in the electrodesupporting membrane. In this embodiment, the supporting member 101 is inthe form of an elongated block having saw cuts 103 and 104 extendingfrom opposite ends of the block in an overlapping relationship. Whilesaw cuts have been referred to for the sake of convenience ofdescription, it will be understood that the resulting slots may beproduced in any known manner. The membrane 106 is or may be in the formof a hose or tube 108 which lits around the supporting member 101. Theprinter bar 109 is cemented as before or otherwise suitably secured tothe membrane 106 and the block 101 is grooved as indicated at 111 toprovide relief for the back surface of the membrane at and adjacent theprinter bar. An f adjusting screw 114 is engaged in a tapped hole 116 inthe bar 101 and extends into contact with one face of saw cut 103. Byturning this screw so that it enters the block it will be seen that thesaw cut 103 will be spread, thereby expanding the block and placing thetubular membrane 108 under tension. Another adjusting screw 118 isprovided which is threadedly engaged in a tapped hole 119. A hole 121freely accommodates the shank of this screw. It will be seen from thedrawing that when the adjusting screw 118 is tightened the saw cut 104will be expanded. But suitably setting the screws 114 and 118 a uniformtension may be provided in the tubular membrane 108.

As indicated above in connection with the supporting member 81, theblock 101 may be secured in a recorder as shown in Fig. 1 of thedrawings.

Having now described the invention, what is claimed and desired to besecured by the Letters Patent is the following:

1. In combination in facsimile apparatus, a rotary drum having a helicalmember supported thereon, an elongated printer bar arranged to bepositioned in cooperative relationship to the drum and helical member soas continuously to bring said elements to bear upon each other, arecessed support element for said printer bar, a resilient stripspanning the recess in the support element for positioning the printerbar on the support element, the thickness of said strip being smallcompared with its width transversely of the bar, said resilient stripoverlapping and being effectively supported by the support element ateach side of the recess, the base of the printer bar being securedagainst the resilient strip, said printer bar being of a width less thanthe width of the recess so that a portion of said resilient strip is inshear, means to feet a record receiving strip between the drum and theprinter bar, and means to hold the recessed support element in positionto maintain contact between the printer bar and the helix.

2. The combination of claim 2 wherein said last named means provides foradjustment of the position of the recessed support element.

l 3 A printer bar and printer bar support for a facsimile recordercomprising an elongated flexible printer bar having a fiat body portionand a projecting recording edge, the width of said printer bar bodyportion being relatively great with respect to its depth whereby saidbar is flexible in a plane normal to its width, a support for said barcomprising an elongated member having an elongated recess therein, aexible strip secured to said elongated member to cover said recess, andsaid printer bar being secured to said flexible strip 1n alignment withand substantially centered with respect to said recess.

4. The printer bar and printer bar supporting means of claim 3 whereinthe width of said bar is substantially less than the width of saidrecess whereby a damping eifect is provided by the ilexible memberbetween each edge of said bar and each edge of said recess.

5. In combination an elongated printer bar having a flat body portionand a projecting recording edge, the width of said printer bar bodyportion being relatively great with respect to its depth whereby saidbar is 'flexible in a plane normal to its width, a support for saidprinter bai comprising a resilient elongated membrane, said bar beingsecured to said membrane, an elongated member havinga recess therein,said bar being positioned opposite said recess, and means slidablyreceiving said recessed member, said last named means having means formoving said recessed member outwardly whereby to tension said resilientsupporting member.

6. combined printer bar and printer bar holder comprising a resilientmember, a support for said member comprising an elongated block having arecess therein, an elongated printer bar carried by said resilientmember opposite said recess, and means associated with said block totension said resilient member, said printer bar having a at body portionand a projecting recording edge, the width of said body portion beingrelatively great with respect to its depth whereby said bar is flexiblein a plane normal to its width.

7. -combined printer bar and printer bar holder comprising a tubularresilient member, a support for said tubular member comprising anelongated block having a recess therein, said tubular membersurrounding. said block, an elongated printer bar carried by saidresilient member opposite said recess, said printer bar having a ilatbody portion and a projecting recording edge, the width of said bodyportion being relatively greatwith respect to its depth whereby said baris ilexible 1n a plane normal to its width, and means in said block totension said resilient member.

8. The combined printer bar and printer bar holder of claim 7, saidrecessed block having slots therein eX- tending substantially the lengthof said block, and means for expanding said block whereby to alter thetension in said resilient member.

9. A printer bar for a facsimile recorder comprising an elongatedflexible bar having a at body portion and a projection ending in arecording edge thereon, the body portion of said bar being relativelywide, said projection being centered on said at body portion, the sui'nof the thickness of the body portion of said bar and said projectingbeing small as compared with the width o f said bar whereby said bar isrelatively flexible in a direction parallel to the plane of saidprojection and is relatively rigid in a plane at right angles to theplane of said projection.

References Cited in the tile of this patent UNITED STATES PATENTS Number

